Control apparatus



Dec. 4, 1945. s.' CRUM 4 2,390,425

CONTROL APPARATUSV Fiied oct. 14, 1942 l J0 /05 /llil 30 Patented 4, 194s UNITED STATES PATENT. OFFICE stephen om, Minneapolis, Minn., asignar io ,M Minneapolis-Honeywell Regulator Company. Minneapolis, Minn., a corporation of Delaware Appllcatllm October 14, 1942, Serial N0. 461,967

employing liquid-cooled engines, the scoops'direct a flow of air through the radiator of the cooling system. The amount of cooling is controlled by adjusting the scoops which are pivotally mounted so as to project .from the sides of the aircraft in which: position exceedingly high pressures are exerted upon the scoops. Accordingly, it is imperative' that the means for adjusting the scoops be capable of maintaining the same in an ad- Justed position in order that a substantially conetant engine temperature may be maintained.

Moreover, it is further desirable that the adjusting means be susceptible of fine adjutment in order that the scoops may be positioned in accordance with small' temperature variations, thereby providing a sensitive control system.

'In the co-pending application of Willis H. Gille, Serial No. 439,673, filed April 20, 1942, a temperature control system for aircraft is disclosed in which an electric motor actuates a poppet valve through a plurality of cam means. The valve controls the flow of uid under pressure to a reversible hydraulic `servo-motor which 'in turn motivates the temperature control flaps. In the co-pending application of Hubert T. Sparrow. Serial No. 461,956, filed Oct. 14, 1942, a temperature control system for aircraft is disclosed in which a solenoid actuated piston valve controls the ow of iluid under pressure to a reversible hydraulic servo-motor which in turn motivates the temperature control scoops of the aircraft.

The present invention contemplates an `aircraft temperature control system in which a sole,

noid actuated poppetvalve controls the flow of iluid under pressure vto a reversible hydraulic servo-motor which in turn motivates the scoops of the aircraft. The present invention combines the desirable inherent sealing characteristic of poppet valves withV the effective, positive, and reliable action of a solenoid motive means to provide an inexpensive and expeditious valve control structure.

A broad object of the present invention, there, is generally to provide improvements in temperature control systems for aircraft. A Another object oi this invention isto provide 2 Claims. l(Gl. 121-40)` control ,ap.

novel valve control apparatus which is particularly adaptable for use in aircraft control systems.

A further object of the present` invention is to provide a novel valve structure comprising a Vpair of solenoid actuated poppet valves and a pair of check valves which prevent fluid iiow through the valve when the solenoid valves are deenergized and provide fluid flow throughthe valve in opposite directions when the solenoid `valves are selectively energized. Y

Still other objects are those expressly stated or implied in the following specification and claims reference being had to the accompanying drawing, in which:

Figure 1 illustrates diagrammatically the application of my invention to an temperature control system, and

Figure 2 is a sectional elevational view of the solenoid valve structure diagrammatically shown inFigure 1. y

Referring to Figure 1 in which a portion. ofan airplane is shown diagrammatically in elevation, the numeral B generally designates an engine of the liquid cooled type for driving a propeller l.

aircraft engine The engine 6 is cooled by a suitable fluid, suchJ as Prestone, which is circulated through the engine and a radiator 8, the radiator being ccnnected to the engine by suitable conduit 9, Ill in the usual manner.

The fluid in the radiator 8 is cooled by the passage of air therethrough, and the amount oi.' cooling is controlled by a pair of scoops II, I2 which are pivotally mounted on the cowl I3 of the airplane in such a manner as to be pivotally adjustable outwardly of the cowl. The front scoop II admits the air which flows through the radiator 8 in the direction of the arrows and the rear scoop I2 serves as a discharge port for the air as clearly seen in the drawing.

A reversible hydraulic servo-motor I4, of conventional design is provided for adjusting the scoops I I, I2. The motor I4 comprises a cylinder I5 and a piston I6 mounted for reciprocative movement in the cylinder. .A pistonrod Il'is secured to the piston I6 and extends through an end of the cylinder I5 in fluid tight relation therewith.

2 crank arrangement, it is obvious that both scoops I I, |2 may be adjusted to the same extent for each movement of the piston I6.

Fluid for operating the motor |4 is supplied by a low pressure receiver or sump 25. The fluid is drawn from the sump through conduit 26 to the pump and pressure chamber 21 and thence sup; plied under pressure through conduit 29 to a solenoid actuated control valve generally designated 29. Conduit 39 is provided for the return of low pressure fluid from the Also leading from the valve 29 are conduits 3|, 32 which communicate with the left and right ends of the cylinder I4 respectively. l.

The valve `29 is providecrwith a pair of electric lead wires 33, 34 and may be grounded to the airplane structure in any convenient manned being schematically grounded through grounded connections 35 as shown in the drawing. As will hereinafter appear, when a circuit is completed through the terminal 33 to ground, the valve 29 provides a fluid iiow causing the piston I9 to move to theleft. When a circuit is completed through the terminal 34 to ground the valve 29 provides a fluid now causing the piston I6 to move to the right. Upon deenergization of the valve 29 all of the parts leading therefrom are automatically closed thereby hydraulically locking the piston |6 in its adjusted position.

"It is to be understood that any convenient means may be employed for controlling the energization of the valve 29. Such means may comprise manually controlled switch means disposed at the pilots station, or automatic means responsive to engine temperature which may, for example, be a three wire temperature control system or a follow-up control system of the balanced circuit or bridge type.

In the drawing a bridge circuit, generally designated by the numeral 36, is shown as best being illustrative of the principles involved in my invention. -The bridge circuit 36 comprises a temperature responsive resistance element 31 which is preferably inserted into the conduit 9 at the point where the hot fluid leaves the engine, as shown. The circuit 36 further comprises input terminals 39, 39, and output terminals 49, 4|.

valve 29 to the sump 25.

' A first arm of the bridge circuit 36 includes the k temperature responsive element 31 which is connected between the input terminal 39 and output terminal 49. The second arm of the bridge circuit is connected between the output terminal 49 and the input terminal 39 and includes a xcd resistor 42. The third arm of bridge circuit 36 is connected between input terminal 39 and output terminal 4| and includes a fixed resistor 43, a conductor 44, that portion of a slide wire resistor between its right hand terminal and its cooperating slider 46, and slider 46. The fourth arm of the bridge circuit 36 includes slider 46, that portion of slide wire resistor 45 between its left hand terminal and the slider 46, a variable resistor 41, and a conductor 49, the fourth arm-being connected betweenthe output terminal y4| and the input terminal 39. Slide wire 45 and slider 46 comprise a rebalancing potentiometer for the lbridge circuit 36, the slider46 being operatively connected to the piston rod I1, as shown, to provide a follow-up function. The purpose of resistor 41 is to provide means for adjusting the control point of the system. Adjustment of the resistor 41 determines that temperature of the iiuid in conduit 9 adjacent to element 31 which causes the bridge circuit 36 to be balanced for a given position of the slider 46 with` respect to the slide wire 45. A variable resistor 49 and conductor 59 are connected in parallel with the conductor 44 and slide wire resistor 45. The purpose of resistor 49 is to providemeans for regulating the amount of movement of slider 46 necessary to correct a given unbalance ofthe bridge circuit 39.

Bridge input terminals 38,39 are connected to a transformer secondary winding 5| through conductors 52, 63 respectively. Bridge output terminal 49 is connected to an input terminal 54 of an electronic amplifier 55through a conductor 56. Amplifier 55 may be `of any desired type but is preferably oi the type disclosed in Figure 2 of the co-pending application of Albert E. Upton, Serial No. 437,561 filed April 3, 1942. Output terminal 4| of bridge circuit 36 is connected through ground connections 51 and 56 to amplifier input terminal 59.

Amplifier 55 has a pair of power supplyA terminals 69 and 6| which are connected to a transformer secondary winding 92 through conductors 562,

64, and a pair of selectively energizable output terminals 65 and 66. Input terminal 59, through ground connections 59, serves as a common return terminal for the output terminals 65 and 66.

Output terminal 65 is connected through a conductor 61, a Winding 69 of a relay 69, a conductor 19. one-half of transformer secondary winding 1|, and a conductor 1-2 to ground at 13.

Output terminal 68 is connected through a conductor 14, a winding 15 of a relay 16, a conductor 11, the other half of transformer secondary winding 1| and thence through conductor 12 to ground at 13. f.

Transformer secondary windings 5|, 62 and 1| comprise parts of a transformer generally designated by the numeral 18. Transformer 18 further comprises a primary winding 19 which is supplied with alternating current by means of an inverter 89 of any well-known type. The inverter is supplied with direct current from a battery 8| through conductors 92, 83.

The negative side of the battery 9| is grounded through connections 94. The positive side ofthe l battery is connected through a. conductor with movable contacts 86 and 81 of relays 69 and 16l respectively. The Vfixed contacts 88 and 89 of relays 69 and 16 are connected through conduct-ors 99 and 9| with terminals 34 and 33, respectively, of control valve-29.

When the relays 69, 16 are deenergized, the contacts 96, 98 and 91, 99 assume the openposition, as seen in the drawing, by any suitable means such as spring return means. When the relay 69 is energized, a plunger 92 drives the contact 86 into engagement with Athe contact 88, and when the relay 16 is energized, a plunger 93 drives the movable contact 91 into engagement with the contact 89, I

Referring now to Figure 2 in which the control valve 29 is shown in detail, it is seen that the valve comprises a valve body 94 which may be formed by casting or fabricating the same or by any other convenient means.

The valve body 94 comprises an inlet port` 95 to which the conduit 28 is secured. Port 95 communicates with an inlet chamber, 96 which in turn communicates with a pair of intermediate chambers 91 and 99. Disposed between the inlet chamber 96 and intermediate chambers 91, 98 are a pair of check valves 99, |99 for controlling fluid flow between the chambers.

The check valves 99, |99 are maintained in position, as shown, by a pair of coil springs |9I, '|92 which may conveniently be seated in plugs |93,

|04 threaded into the valve body 84, as sho From the foregoing it is obvious that if the iluid pressure in chamber 98 exceeds that in the chambers 91, 98 and the force exerted by the springs |02, that the valves will yieldably permit; uid ow from the inlet to the intermediate chambers. On the other hand, when the pressures in the chambers are equal the compression of the springs |0|, |02 securely seats the valves 99, I 00 to `prevent uld flow from the intermediate to the inlet chamber. A

The intermediate chambers 91, 98 communicate with a pair of controlchambers |05, |08 respectively. Leading from the control chamber is a control port |01 to which the conduit 3| is secured, and an exhaust port |08 to which the conduit 30 is secured. In like manner, a control port |09 to which the conduit 32 is secured and an exhaust port 0 to which conduit 30 is secured, lead from the control chamber |08.

Communication between the intermediate chamber 91 and control chamber |05 `and be- I tween the control chamber |05 and the exhaust port |08 is controlled by a double faced lpoppet valve In like manner, communication between theintermediate chamber 98 and control chamber |08 and between the control chamber |08 and the exhaust port ||0 is controlled by a poppet valve ||2 which may be identical with valve To facilitate the assembly of th'e valve 29 and the machining of the properseats for the valves ||'2, the control ports |05, |08 may extend outwardly of the valve body 94 and be closed by plugs ||3, ||4 .through which the ports |08, ||0 may extend as shown.

'Ih'e valves ||2 are actuated by a. pair of solenoid assemblies ||5, ||8 which may be identical. Each assembly H5, 8 comprises a magnetlodisc ||1, I8 which are secured in uid tight relation to the valve body 94. Supported on the I Y discs ||1, ||8 are a. pair of solenoid windings H9,

| having centrally thereof non-magnetic tubing l2 I, |22 and outwardly thereof insulation material |23, 2l to insulate the windings from their respective housings |25, which are pressed to discs I1, I8 respectively.

Leads 33 and'|21 for winding ll9'are brought through housing |25 in any suitable fluid tight manner, the lead |21 Vbeing grounded to the valve body 94 as shown. Similarly, leads 3Q and |28 for winding |20 are brought out through housing |28 in any suitable fluid tight manner, the lead |29 being grounded to the valve body 94 as shown.

VCooperatively associated with the windings I9, |20 are magnetic plungers |29, |30-respectively. The plunger 29 is connected to the valve by a stem |3|, arid the upper end of the plunger |29 carries a pedestal |32 upon which is supported a. coil spring |33. The spring |33 bears against the p housing |25 to bias the yvalve to close the port |08. Similarly, the plunger is connected to the valve 2 by astem |34 and carries on its upper end a pedestal |35 upon which is supported a coil spring |36. The spring |35 bears against the housing |28 to bias the valve ||2 to close the port ||0.

It is to be noted that the intermediate chambers 91, 98 communicate with the solenoid assem- -blies ||5, IIS. Accordingly, the fluid is free to circulate through the windings 9, |20 te cool the same as well as to lubricate the moving parts.

When the windings 9, |20 are deenergized, the valves 2 close the ports |08, l I0 leading to the low pressure sump 25. Accordinsly. the

check valves 89, |00 permit a one-way fluid` ilow until the pressure of theiluid in the valve 29 and cylinder |5 is everywhereV the same and equal to the pressure oi' the fluid in the pump 21. When this static pressure condition is reached the valves 99, |00 close under power of their associated springs |0|, |02 respectively. Any tendency of th'e piston I6 to move when this condition is reached tends only to further seat the valves 89. |00. ||2 due to the inherent seating characteristics of poppet valves. When one or the other of solencids 5, ||8 is energized., the static pressure condition is unbalanced upon the opening of the low pressure or exhaust port controlled by th' solenoid energized. Direct communication between the inlet port and the exhaust port thus opened is cut olf by the valve actuated. However, communication is established from one side of the piston I8 through the control chamber of the energized solenoid. thus reducing such' pressure. The piston thensmoves and this reduces the pressure in the control chamberof the deeneregized solenoid. The proper check valve then permits iiuid flow into the control chamber of the deeneregized solenoid.

The amplifier 55 is so constructed that when an A'alternating signal of a predetermined phase is applied to theinput terminals 54 and 59, that branch of the output circuit extending through output terminal and relay 89 is energized. When an alternating current signal of the opposite phase is applied to input termina-ls 54 and 59, the other branch of the output 'circuit including -terminal 88 and relay 18 is energized. It will therefore be apparent that the relays 89 and 18 are selectively energized in accordance with the direction of unbalance of the bridge circuit 38.

In operation, shown in the drawing, the scoops 2 are half way open and the engine 8 is at the desired temperature. Let it be assumed that the temperature adjacent the temperature responsive element 31 increases above the desired value. This increases the resistance between input terminal 38 and output terminal 40 of bridge circuit 35 which unbalances the bridge in such a direction that an alternatingpotential is applied to amplifier 55 with the proper phase relationship to cause energization of the relay winding 88. Energization of relay winding 68 causes contact86 to move into engagement with contact 88, thereby completing an energizing circuit for winding ||9 which may be traced as follows: from battery 8|, through conductor 85, 'contacts 88, 88, conductor 9|, lead' established between the left-hand end of cylinder |5 and the sump 25 by way of conduit 3|, chamber |05, the port |08, and conduit 30. `The pressure on the -left-hand side of piston |8 is thereby reduced and the piston starts moving towards the left. Such leftward movement of the piston reduces the pressure on the right-hand side of the piston which is in communication with the intermediate chamber 98 by way of conduit32, chaml ber |08, and the intermediate chamber 98. As a result of this reduction in pressure, the high pressure fluid coming from pump 21 by Vway ol' conduit 28 and inlet chamber 98 forces open check valve |00 to let more uid into this Portion of the with the parts in the position" lcorresponding opening movement ot scoops into this portion of the system.

system, thereby again building up the pressure on the right-hand side ot piston Il. Piston Il thus continues moving to the lett.` Such movement of piston I6 to the left drives 'the slider Il to the left, thereby increasing the resistance between bridge input terminal 38. and output terminal II. When this increase has been suilicient to balance the i'ncreased resistance between lnputterminal 38 and output terminal l due to the increase in engine temperature, the bridge is again balanced, wherewinding II9 and returns valve III to the position shown in Figure 2. draulically locked in its new position. This leftward movement of the piston I6 which has just taken place also moved scoops II and I2 further open so as to increase the circulation of cooling air over the radiator 9. In this manner, every rise in engi ne temperature is accompanied byla and I2.

If the engine temperature decreases below the value it is desired to maintain, the bridge is unbalanced in the opposite direction, thereby causing energization of winding 16 of relay'1l. Energization of relay 16 causes the engagement of contacts 61, 89`thereby completing a circuit to winding I20 which may be traced as follows: from battery 8| through conductor 96, contacts 81, 99, conductor SIL-lead 34, winding |20, and through ground connections |28, 35, and back to battery 8l. Upon energization of winding |20, plunger |39 is drawn upwardly moving valve II2 out of engagement with the port I I9 and into a position to close oli communication between chambers 99 and |06. Opening of port II9 establishes communication between the right-hand side of piston I6 and the sump 25 by way of conduit 22. the now open port III! and conduit 99. The pressure on the right-hand side of piston I6 is thus reduced and the higher pressure on the left-hand side thereof begins moving piston I6 to-the right This higher pressure is contained within .the closed'portion of the system comprised by the conduit 3|, the control chamber I, and the intermediate chamber 91. As'this pressure drops suiciently, the high pressure from pump 21 going through conduit 28 to inlet chamber 96 will force open check valve 99 ito permit further fluid to flow Such right-hand movement of piston I9 moves slider 46 to the right and also moves scoops Il and I2 towards closed position. Such movement of slider 46 tends to rebalance the bridge circuit. When .the'bridge circuit has been completely rebalanced, relay 16 is deenergized which in-turn deenergizes winding I2Il and returns valve II2 to the position shown in Figure 2. The piston I6 is thereby again hydraulically locked in its new The piston I6 is now hy-r,

4upon relay 69 is deenergized. This deenergizes Il and I2 are maintained the flow of air position and the scoops more nearly closed so as to reduce through the radiator 9 to thereby lessen the coolins effect on the engine 9.

From the foregoing, it will be apparent that I have provided a novel solenoid actuated puppet valve mechanism in combination with the requisite check valves and piping' -to bring about a system in which the servo-motor is hydraulically locked in each and every new position which it assumes as a result of changes in the temperature of the cooling fluid for theengine. While I have shown and described but a single embodi- 'ment of my invention, many changes may be made by those skilled in the art without departing from the spirit thereof and I therefore intend to be limited only by the scope of the claims appended hereto.

I claim as my invention: Q l 1. A valve for controllingfiuidnm comprising in combination, a valvebody, an inlet port, a pair of control'ports in communication with said inlet port, a pair of spring loaded check valves intermediate said inlet and said control ports, a pair of outlet ports incommunication with said inlet and said control ports, a control valve intermediate said inlet and each outlet port and controlling the direction of flow through said control ports, said control valves providing means including said check valves for normally resistlng flow through the device in either direction, said means also including a solenoid actuating member in iluid tight association with said valve body and operably associated with each control valve, and spring means :for returning and maintaining said control valves in normal position.

,2. In a control apparatus, comprising in combination, a cylinder and piston, a valve housing ports and control ports in communication with said inlet port, a normally closed spring loaded check valve positioned between said inlet -port and each of said control ports, a control valve disposed intermediate each check valve and the outlet vport associated therewith, said control valves being disposed to normally provide an equalized pressure in imposed ends of said cylinder, said control valves also providing means for selectively bleeding eitherend .of said cylinder to cause opera-ble movement of said piston in relation to said bleeding, said check valves and sid control valves when in normal position providing means for hydraulically locking said 4piston against movement, means for operating said control valves independently of each other and said check valves, and said check valves being disposed to operate independently of said control valves.

STEPHEN CRUM. 

